Understanding the Self-Assessment Tax Return
The self-assessment tax return system in the United Kingdom is designed for individuals who are self-employed, freelancers, or business owners. It’s a way for HM Revenue and Customs (HMRC) to collect Income Tax from those who are not under the Pay As You Earn (PAYE) system.
As per the recent data from HMRC, in 2024, around 12 million people in the UK were required to file a self-assessment tax return [source]. This means that a significant proportion of the working population needs to understand where and how to file a self-assessment tax return.
Where to File a Self-Assessment Tax Return
Filing a self-assessment tax return is straightforward and can be done through three main methods:
- Online through the HMRC website
- Through a tax preparation software
- By post
Online through the HMRC Website
The most convenient method to submit your self-assessment tax return is online, directly through the HMRC website [source]. This platform is user-friendly and provides prompts to guide you throughout the process.
However, to use this method, you need to register for an online account with HMRC. Registration is a simple process that can be done on the HMRC website and usually takes up to seven working days.
Through a Tax Preparation Software
You can also file a self-assessment tax return using commercial tax preparation software. This method is especially beneficial for those with more complex tax situations, as these software packages often provide additional guidance and support.
However, it’s essential to ensure that the software you choose is compatible with the HMRC system. You can check this on the HMRC’s list of recognized software [source]).
By Post
The third option is to file your tax return by post. You can download and fill in the SA100 tax return form, along with any supplementary pages if necessary. Once completed, you can mail it to the HMRC.
Remember, the deadline for paper returns is earlier than for online submissions. In 2025, the deadline for paper returns was 31st October, while the deadline for online returns was 31st January of the following year [source].
Preparation is Key
No matter which method you choose to file your self-assessment tax return, preparation is key. Ensure that you keep thorough records of your income and expenses throughout the year. Also, remember to register for self-assessment and file your tax return before the deadline to avoid penalties.
Conclusion
Understanding where to file a self-assessment tax return is crucial for freelancers, self-employed individuals, and business owners. Options include the HMRC website, tax preparation software, or by post. Remember to prepare well and file your return before the deadline to ensure a smooth tax filing process.
